How should I practice Place a Service Table Near All Customers?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Google phone screen problems in FastPrep.

Is Place a Service Table Near All Customers associated with Google?

FastPrep tags this as a Google phone screen coding practice problem when the problem catalog has that company and stage context.

Place a Service Table Near All Customers

Google● MediumNEW GRADPHONE SCREEN

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Problem statement

A rectangular restaurant grid contains 0 for an empty cell, 1 for a customer table, and -1 for a wall.

Choose one empty cell for a service table. Movement is allowed one cell up, down, left, or right and cannot pass through walls. Minimize the sum of shortest-path distances from the service table to every customer table.

Return the chosen coordinate [row,column]. Break ties by smaller row, then smaller column. Return [-1,-1] if there is no customer table or no empty cell can reach every customer table.

Function

bestServiceTable(grid: int[][]) → int[]

Examples

Example 1

grid = [[1,0,0],[0,-1,0],[0,0,1]]return = [0,1]

The cells [0,1] and [1,0] both have total distance four; row-major tie-breaking chooses [0,1].

Example 2

grid = [[1,-1,0],[0,-1,1],[0,0,0]]return = [1,0]

Among cells reaching both customers, [1,0] minimizes the total distance.

Example 3

grid = [[1,-1,0],[-1,-1,1],[0,0,0]]return = [-1,-1]

No empty cell can reach both customers.

Constraints

1 <= rows, columns <= 200.
Every cell is -1, 0, or 1.
The grid contains at least one customer table.